1. Field of the Invention
The present application generally relates to writing data to a removable data storage medium, and more particularly to introducing a noise signal into a read-back signal when data is written to a removable data storage medium.
2. Related Art
In a conventional data storage system that uses a removable data storage medium, data can be stored on the removable data storage medium using one data storage device and retrieved using another data storage device. Thus, the removable data storage medium can be interchangeably used in multiple data storage devices. Conversely, a data storage device can interchangeably use multiple removable data storage media. For example, when the removable data storage medium is a magnetic tape cartridge, data can be stored onto a magnetic tape in the magnetic tape cartridge using one tape drive, then the stored data can be retrieved from the magnetic tape cartridge using another tape drive.
During a write process, when data is stored on a removable data storage medium, a read-after-write operation can be used to check for errors in writing the data to the removable data storage medium. More particularly, during the write process, when data is written to the removable data storage medium by a write head, the data written to the removable data storage medium is read by a read head to generate a read-back signal. The read-back signal can be used to determine if an error occurred in writing the data to the removable data storage medium. If an error is detected, the data can be re-written.
During a read process, the data stored on the removable data storage medium is read by the read head to retrieve the data from the removable data storage medium. Thus, data written to the removable data storage medium is read during the write process to check for errors in writing the data and read during a read process to retrieve the data from the removable data storage medium. Because the removable data storage medium is interchangeable, the data can be read during the write process by one read head in a first data storage device and read during the read process by another read head in a second data storage device. However, in some circumstances, the read head in the first data storage device may be able to read the data during the write process but the read head in the second data storage device may not be able to read the same data during the read process. Thus, in these circumstances, because the data was not re-written, the data stored on the removable data storage medium by the first data storage device cannot be retrieved using the second data storage device, which reduces the interchangeability of the removable data storage medium.